
#include <iostream>

using namespace std;

class school_t
{
public:
    static void add_lib_books(string book)
    {
        lib += book;
    }

public:
    string tower;
    string lake;
    static string lib;
};

//类外实始化
string school_t::lib = "beijing lib:";

int main(void)
{
    school_t a, b, c, d;

    cout<<sizeof(a)<<sizeof(b)<<sizeof(c)<<sizeof(d)<<endl;

    cout<<school_t::lib<<endl;
    school_t::lib = "China lib";
    cout<<school_t::lib<<endl;
    cout<<a.lib<<endl;

    school_t::add_lib_books("time get si");
    cout<<school_t::lib<<endl;

    return 0;
}

